Capacitively coupled connector junctions having parallel signal paths and related connectors and methods

ABSTRACT

Coaxial connector junctions include a first coaxial connector that has a first center conductor extension and a first outer conductor extension and a second coaxial connector that is mated with the first coaxial connector, the second coaxial connector including a second center conductor extension and a second outer conductor extension. A communications path between the first outer conductor extension and the second outer conductor extension includes a first capacitively coupled outer conductor communications path and a second galvanically coupled outer conductor communications path.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority under 35 U.S.C. §119 to U.S.Provisional Patent Application Ser. No. 62/088,798, filed Dec. 8, 2014,the entire content of which is incorporated herein by reference as ifset forth in its entirety.

FIELD OF THE INVENTION

The present invention is directed generally to connectors and, moreparticularly, to connectors for electrical cables.

BACKGROUND

Coaxial cables are a known type of electrical cable that may be used tocarry radio frequency (“RF”) signals. Coaxial cables are widely used incable television networks, cellular communications systems and otherhigh bandwidth applications as signals may experience less attenuationwhen transmitted over coaxial cable than various other types ofelectrical cables at the high frequencies used in such applications.FIG. 1 is a schematic perspective view of a conventional coaxial cable10 that has been partially cut apart to reveal its internal structure.As shown in FIG. 1, the coaxial cable 10 has a center conductor 12 thatis surrounded by a dielectric spacer 14. An outer conductor 16 surroundsthe center conductor 12 and the dielectric spacer 14. The outerconductor 16 is typically grounded and serves as an electrical shieldthat reduces signal radiation (and hence signal attenuation) of the RFsignal carried on the center conductor 12. Finally, a cable jacket 18surrounds the outer conductor 16 to complete the coaxial cable 10.

A coaxial connector refers to a connector that may be attached to an endof a coaxial cable to “terminate” the coaxial cable so that the cablemay be attached to an apparatus or the connector of another terminatedcoaxial cable. By terminating a first coaxial cable with a coaxialconnector, the coaxial cable may be connected to, and subsequentlydisconnected from, (a) a second coaxial cable that is terminated with a“mating” coaxial connector (i.e., a coaxial connector that is designedto interface with the coaxial connector on the first coaxial cable) and(b) an apparatus that includes a mating coaxial connector. Two coaxialconnectors that are connected together (“mated”) are referred to hereinas a “coaxial connector junction.”

In a typical arrangement where a coaxial connector junction is used toconnect a first coaxial cable to a second coaxial cable (or,alternatively, to an apparatus), a first coaxial connector is terminatedonto the first coaxial cable and a second coaxial connector isterminated onto the second coaxial cable. The first coaxial connectormay include a center conductor extension (often in the form of a pin ora post) that is connected to the center conductor of the first coaxialcable and an outer conductor extension (typically in the form of aconnector body) that is connected to the outer conductor of the firstcoaxial cable. The second coaxial connector may also include a centerconductor extension (often in the form of a sleeve or a contact spring)that is connected to the center conductor of the second coaxial cableand an outer conductor extension (typically in the form of a connectorbody) that is connected to the outer conductor of the second coaxialcable. The center conductor extension of the first coaxial connector ismated with the center conductor extension of the second coaxialconnector, and the outer conductor extension of the first coaxialconnector is mated with the outer conductor extension of the secondcoaxial connector. The first coaxial connector typically includes athreaded coupling nut and the second coaxial connector typicallyincludes a threaded surface (or vice versa). By threading the couplingnut of the first coaxial connector onto the threaded surface of thesecond coaxial connector the two coaxial connectors may be drawntogether into secure electro-mechanical engagement. When the first andsecond coaxial connectors are mated together, the coaxial connectorjunction is formed that electrically connects the center conductor ofthe first coaxial cable to the center conductor of the second coaxialcable, and that electrically connects the outer conductor of the firstcoaxial cable to the outer conductor of the second coaxial cable.

Passive Intermodulation Distortion (PIM) is a form of electricalinterference/signal transmission degradation that may occur atinterconnections, such as interconnections between two coaxialconnectors, where a non-linearity is introduced into the connection,either as initially installed or due to electro-mechanical shift overtime. Interconnections may shift due to mechanical stress, vibration,thermal cycling, and/or material degradation. PIM can be an importantinterconnection quality characteristic, as PIM generated by a single lowquality interconnection may degrade the electrical performance of anentire RF system. Thus, the reduction of PIM via connector design istypically desirable. One method of reducing PIM is to use coaxialconnector junctions that employ capacitive interconnections rather thangalvanic interconnections.

SUMMARY

Pursuant to embodiments of the present invention, coaxial connectorjunctions are provided that include a first coaxial connector that has afirst center conductor extension and a first outer conductor extension.A second coaxial connector is mated with the first coaxial connector.The second coaxial connector includes a second center conductorextension and a second outer conductor extension. A communications pathbetween the first outer conductor extension and the second outerconductor extension includes a first capacitively coupled outerconductor communications path and a second galvanically coupled outerconductor communications path.

In some embodiments, the first capacitively coupled outer conductorcommunications path may be configured to substantially pass signalshaving frequencies in a first frequency range while substantiallyblocking signals having frequencies in a second frequency range thatencompasses frequencies that are lower than the first frequency range,and the second galvanically coupled outer conductor communications pathmay be configured to substantially pass signals having frequencies inthe second frequency range while substantially blocking signals in thefirst frequency range.

In some embodiments, a communications path between the first centerconductor extension and the second center conductor extension mayinclude a first capacitively coupled center conductor communicationspath and a second galvanically coupled center conductor communicationspath. In such embodiments, the first capacitively coupled centerconductor communications path may be configured to substantially passsignals having frequencies in a first frequency range whilesubstantially blocking signals having frequencies in a second frequencyrange that encompasses frequencies that are lower than the firstfrequency range, and the second galvanically coupled center conductorcommunications path may be configured to substantially pass signalshaving frequencies in the second frequency range while substantiallyblocking signals in the first frequency range.

In some embodiments, the first center conductor extension may include anouter shell that defines an internal cavity, and the first capacitivelycoupled center conductor communications path may extend along the outershell and the second galvanically coupled center conductorcommunications path may extend through the internal cavity. In suchembodiments, the second galvanically coupled center conductorcommunications path may include an inductance that is at least partlywithin the internal cavity.

In some embodiments, the first outer conductor extension may include anouter shell that defines an internal cavity, and the first capacitivelycoupled outer conductor communications path may extend along the outershell and the second galvanically coupled outer conductor communicationspath may extend through the internal cavity. In such embodiments, thesecond galvanically coupled outer conductor communications path mayinclude an inductance.

In some embodiments, the first outer conductor extension may be spacedapart from and circumferentially surround the first center conductorextension and the second outer conductor extension may be spaced apartfrom and circumferentially surround the second center conductorextension.

In some embodiments, the first capacitively coupled outer conductorcommunications path and the second galvanically coupled outer conductorcommunications path may comprise parallel paths that are configured tocarry signals in different frequency ranges.

Pursuant to further embodiments of the present invention, methods ofreducing corrosion in a connector junction between a first electricalconnector and a second electrical connector are provided in which afirst capacitively coupled communications path is provided between afirst conductor of the first connector and a first conductor of thesecond connector. A second galvanically coupled communications path isprovided between the first conductor of the first connector and thefirst conductor of the second connector. The second galvanically coupledcommunications path is electrically parallel to the first capacitivelycoupled communications path and is configured to maintain the firstconductor of the first connector and the first conductor of the secondconnector at the same electrical potential.

In some embodiments, the first electrical connector may be a firstcoaxial connector and the second electrical connector may be a secondcoaxial connector, and the first conductor of the first coaxialconnector may be an outer conductor of the first coaxial connector andthe first conductor of the second coaxial connector may be an outerconductor of the second coaxial connector.

In some embodiments, the first electrical connector is a first coaxialconnector and the second electrical connector is a second coaxialconnector, and the method may further involve providing a secondcapacitively coupled communications path between a second conductor ofthe first coaxial connector and a second conductor of the second coaxialconnector and providing a second galvanically coupled communicationspath between the second conductor of the first coaxial connector and thesecond conductor of the second coaxial connector. In such embodiments,the second galvanically coupled communications path may be electricallyparallel to the second capacitively coupled communications path and maybe configured to maintain the second conductor of the first coaxialconnector and the second conductor of the second coaxial connector atthe same electrical potential.

In some embodiments, the first capacitively coupled communications pathbetween the first conductor of the first connector and the firstconductor of the second connector may only pass signals above a firstfrequency while the second galvanically coupled communications pathbetween the first conductor of the first connector and the firstconductor of the second connector may only pass signals below the firstfrequency.

Pursuant to still further embodiments of the present invention, methodsof transmitting multiple signals through a coaxial connector junctionformed between a first coaxial connector and a second coaxial connectorare provided. Pursuant to these methods, a first radio frequency signalis capacitively coupled from the first coaxial connector to the secondcoaxial connector and a second low frequency signal is galvanicallycoupled from the first coaxial connector to the second coaxialconnector.

In some embodiments, the second low frequency signal may be a directcurrent power supply signal. In other embodiments, the second lowfrequency signal may be a control signal having a center frequency ofless than 1 MHz.

In some embodiments, the coaxial connector junction may be a centerconductor communications path between a center conductor extension ofthe first coaxial connector and a center conductor extension of thesecond coaxial connector and an outer conductor communications pathbetween an outer conductor extension of the first coaxial connector andan outer conductor extension of the second coaxial connector, and theouter conductor communications path may be a first capacitively coupledouter conductor communications path and a second galvanically coupledouter conductor communications path.

In some embodiments, the first outer conductor extension may include anouter shell that defines an internal cavity, and the first capacitivelycoupled outer conductor communications path may run along the outershell.

In some embodiments, the second galvanically coupled outer conductorcommunications path may include a low pass filter.

In some embodiments, the first center conductor extension may include anouter shell that defines an internal cavity, and the first capacitivelycoupled center conductor communications path may run along the outershell and the second galvanically coupled center conductorcommunications path may run through the internal cavity. In suchembodiments, the second galvanically coupled center conductorcommunications path may include a low pass filter.

Pursuant to still further embodiments of the present invention, coaxialconnectors may be provided that include a center conductor extensionthat has an outer shell that defines an internal cavity and a centerconductor contact that is electrically connected to the center conductorextension and disposed within the internal cavity; an outer conductorextension that is spaced apart from and circumferentially surroundingthe center conductor extension; and a dielectric spacer interposedbetween the center conductor extension and the outer conductor extensionthat electrically isolates the center conductor extension from the outerconductor extension.

In some embodiments, the center conductor contact may be configured tomate with a center conductor contact of a mating coaxial connector.

In some embodiments, the center conductor contact may include a low passfilter.

In some embodiments, the coaxial connector may further include acoupling nut that is configured to releasably attach the coaxialconnector to a mating coaxial connector so that the center conductorextension capacitively couples with a center conductor extension of themating coaxial connector and the outer conductor extension capacitivelycouples with an outer conductor extension of the mating coaxialconnector, and so that the center conductor contact galvanically mateswith a mating center conductor contact of the mating coaxial connector.

In some embodiments, the center conductor extension of the matingcoaxial connector may be an outer shell that defines an internal cavity,and the mating center conductor contact of the mating coaxial connectormay be electrically connected to the center conductor extension of themating coaxial connector.

Pursuant to still further embodiments of the present invention,electrical connectors are provided that include an outer conductorextension having a cable receiving end and a connection end opposite thecable receiving end; a center conductor extension having a first endthat is configured to physically and electrically engage a conductor ofa communications cable that is received within the cable receiving endof the outer conductor extension and a second end that comprises anouter shell that defines an internal cavity; and a center conductorcontact that is within the internal cavity.

In some embodiments, the outer shell may be configured to capacitivelycouple with a center conductor extension of a mating electricalconnector, and the center conductor contact may be configured tophysically engage a center conductor contact of the mating coaxialconnector to provide parallel communications paths between theelectrical connector and the mating electrical connector.

In some embodiments, the center conductor contact may include a low passfilter.

In some embodiments, the outer shell may include an expanded capacitivecoupling surface.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a side partially cut-away view of a conventional coaxialcable.

FIGS. 2A-2C are a perspective view, a perspective cross-sectional viewand an exploded perspective cross-sectional view, respectively, of aconnector junction according to certain embodiments of the presentinvention. FIG. 2D is an enlarged perspective view of a spring contactthat is included in one of the connectors of the connector junction ofFIGS. 2A-2C.

FIG. 3 is a schematic perspective cross-sectional view illustrating aconnector junction according to further embodiments of the presentinvention.

FIG. 4 is a perspective cross-sectional view of a coaxial connectorjunction according to still further embodiments of the presentinvention.

FIG. 5 is a schematic block diagram of a cellular base station that usescoaxial cables connected by coaxial connector junctions according toembodiments of the present invention.

FIG. 5A is a schematic diagram illustrating coaxial connector junctionsin a cellular base station that may be implemented using the coaxialconnector junctions according to embodiments of the present invention.

FIG. 6 is a circuit diagram illustrating an electrical circuit formed bycoaxial connector junctions according to certain embodiments of thepresent invention.

FIG. 7 is a flow chart illustrating a method of preventing corrosion ina connector junction between a first electrical connector and a secondelectrical connector according to embodiments of the present invention.

DETAILED DESCRIPTION

RF signals are transmitted over coaxial cables and connectors in a widevariety of applications. In many of these applications, it may also benecessary to transmit additional signals such as controls signals and/oralternating current (“AC”) or direct current (“DC”) power signals overcabling connections. By way of example, in many cellular base stationapplications, coaxial cables are used to carry RF signals from, forexample, baseband equipment that is located at the bottom of an antennatower (or other structure) to remote radio heads that are located at thetop of the antenna tower. As the remote radio heads are powered devices,it is also typically necessary to transmit DC power up the antenna towerto power the remote radio heads. Additionally, control signals may alsobe transmitted up the tower to control antennas that can be mechanicallyor electrically steered via actuators and/or beam-forming elements. Insome cases, these DC power signals and/or control signals may besimultaneously transmitted over the same coaxial cable that is used totransmit RF signals between the remote radio head and the basebandequipment.

As discussed above, coaxial connector junctions that use capacitiveconnections can be used at cellular base stations and in otherapplications to reduce PIM. Unfortunately, however, a number of problemsmay arise when such capacitively-coupled coaxial connector junctions areused. For example, capacitively-coupled coaxial connector junctionstypically cannot pass low frequency signals or DC power as thecapacitive interfaces acts as an open circuit for such signals.Accordingly, when capacitively-coupled coaxial connector junctions areused, it may be necessary to provide additional cabling and connectorsto carry control signals and/or DC power signals. Additionally, it canalso be more difficult to adequately ground cabling connections thatemploy capacitively-coupled coaxial connector junctions againstlightning strikes, as the capacitively-coupled junction does not providea low-resistance path to ground for the energy of a lightning strike.Accordingly, it may be necessary to ground every segment of acapacitively-coupled cabling connection to ensure that each segment ofthe connection has a low-resistance path to ground, which can beexpensive and/or difficult in some applications. Moreover, inapplications where capacitively-coupled connector junctions are used, anelectric potential difference may result between connector elements thatform the capacitive connections and, if moisture bridges this capacitiveconnection, then this electric potential difference may corrode portionsof the coaxial connectors which can severely degrade the electricalconnection between the two coaxial connectors.

Pursuant to embodiments of the present invention, coaxial connectorjunctions between a first coaxial connector and a second coaxialconnector are provided in which the outer conductor extensions of themated first and second coaxial connectors are configured to provide afirst capacitively coupled outer conductor communications path and thecenter conductor extensions of the mated first and second coaxialconnectors are configured to provide a first capacitively coupled centerconductor communications path. In addition, the mated first and secondcoaxial connectors may also have a second galvanically coupled outerconductor communications path and/or a second galvanically coupledcenter conductor communications path. The second galvanically coupledouter conductor communications path may be disposed in parallel to thefirst capacitively coupled outer conductor communications path, and thesecond galvanically coupled center conductor communications path may bedisposed in parallel to the first capacitively coupled center conductorcommunications path. The second galvanically coupled outer conductorcommunications path and the second galvanically coupled center conductorcommunications path may be configured to pass low frequency signalswhile blocking higher frequency RF signals.

In some embodiments, the second galvanically coupled center and outerconductor communications paths may be used to transmit power (e.g., DCpower) and/or low frequency control signals through the coaxialconnector junction in parallel with RF signals that are transmittedthrough the junction via the capacitively coupled center and outerconductor communications paths. In addition, the second galvanicconnection through the outer conductor extensions may provide a lowfrequency ground path that allows the energy from lightning strikes topass from the outer conductor extension of the first coaxial connectorto the outer conductor extension of the second coaxial connector to agrounding location. The second galvanically coupled center and outerconductor communications paths may also be used to maintain the matingconductor pairs on both sides of the junction (i.e., the two outerconductor extensions or the two center conductor extensions) at the sameelectric potential, which may reduce the tendency for corrosion of thecoaxial connectors at the capacitive junctions.

In some embodiments, a low pass filter may be included on one or both ofthe second galvanically coupled center conductor communications pathand/or the second galvanically coupled outer conductor communicationspath. Thus, while the junction between the conductor extensions of thetwo connectors (e.g., the center conductor extensions of the twoconnectors) may comprise a galvanic interface, a low pass filter may beincorporated along the low frequency communications path in one (orboth) of the connectors. The low pass filter may be implemented, forexample, using an inductor. In some embodiments, the second galvanicallycoupled communications paths may pass through a center portion of thecentral or outer conductor extensions of the mated coaxial connectors(i.e., a portion that is within the body of the conductor extension asopposed to an outer skin thereof) so that the skin depth effect of thecapacitively coupled RF communications path will further isolate the RFsignals from the galvanically coupled (low frequency) communicationspaths. The direct galvanic connections for the low frequency paths maybe implemented using conventional coaxial cable contacts that areprovided in addition to the capacitive connections that form the RFsignal path.

The coaxial connector junctions according to embodiments of the presentinvention may provide a number of advantages over prior art capacitivecoaxial connector junctions. For example, the coaxial connectorjunctions according to embodiments of the present invention maysimultaneously pass two or more of RF signals, low frequency controlsignals, and direct current power. This may allow all three signal typesto be carried up, for example, an antenna tower on a single coaxialcable as opposed to using two or three separate cables, which maysignificantly reduce tower wind and weight loading, decrease cost andsimplify installation. Additionally, the coaxial connector junctionsaccording to embodiments of the present invention may provide improvedelectrical grounding for protection against lightning strikes and mayalso reduce connector corrosion issues that may occur due to adifference in electrical potential across capacitive interconnections.

While the coaxial connector junctions according to embodiments of thepresent invention may provide a number of advantages simultaneously, itwill be appreciated that aspects of the present invention may be appliedin many different ways. For example, in some embodiments, only the outerconductor extensions of the two mated coaxial connectors may have thelow frequency galvanically coupled communications path which is used toreduce degradation of the connection due to corrosion. Thus, it will beappreciated that not all of the advantages need be simultaneouslyachieved.

Example embodiments of the present invention will now be discussed infurther detail with reference to the drawings.

FIGS. 2A-2C are a perspective view, a perspective cross-sectional viewand an exploded perspective cross-sectional view, respectively, of anelectrical connector junction 100 according to certain embodiments ofthe present invention. FIG. 2D is an enlarged perspective view of aspring contact 170 that is included in one of the connectors of theconnector junction 100 of FIGS. 2A-2C. As shown in FIGS. 2A-2C, theelectrical connector junction 100 may be formed by mating a firstelectrical connector 110 with a second electrical connector 150. Thefirst electrical connector 110 may be attached to an end of a firstelectrical cable 102-1 and the second electrical connector 150 may beattached to an end of a second electrical cable 102-2. In FIGS. 2A-2C,the housings of the first and second electrical connectors 110, 150 arenot shown to simplify the drawings and to more clearly illustrate thedesign and construction of the signal current path through theconnectors 110, 150. It will be appreciated that any appropriate housingstructures may be used and that the housings may include matingattachment structures (e.g., a threaded coupling nut on one housing anda threaded surface on the other housing) that may be used to draw theelectrical connectors 110, 150 into firm electro-mechanical engagement.

As is shown in FIGS. 2A-2C, electrical connector 110 includes aconductor extension 120 that has a first end 122 and a second end 124.In the depicted embodiment, the conductor extension 120 is somewhatelongated along the longitudinal axis defined by the first electricalcable 102-1. The conductor extension 120 may have a generally circularshape in cross-sections taken along the longitudinal axis thereof, andthe radius of these cross-sections may vary (e.g., the radius of thecross-sections may be smaller towards the first end 122 as compared tothe second end 124). A conductor 104-1 of the first electrical cable102-1 may be physically and electrically connected (e.g., by the housingof the first electrical connector 110) to the first end 122 of theconductor extension 120. The conductor extension 120 may be formed of aconductive material such as a metal (e.g., copper). As shown in FIGS. 2Band 2C, the first end 122 of the conductor extension 120 may be solidwhile the second end 124 may include an internal cavity 126 that has anopen end. Additionally, the second end 124 of the conductor extension120 may include a lip that forms an annular plate 128 that increases thesurface area of the front surface of the second end 124 of the conductorextension 120. An annular dielectric disk 134 may be attached to theannular plate 128. As discussed below, the annular plate 128 and theannular dielectric disk 134 may form an electrode and a dielectric of acapacitor 106 that is used to capacitively couple RF signals from thefirst connector 110 to the second connector 150 (and vice versa).

The conductor extension 120 further includes a male contact structure inthe form of a conductive post 130 that is mechanically and electricallyconnected to the conductor extension 120. In the depicted embodiment,the conductive post 130 comprises a metal rod that protrudes from a rearsurface of the internal cavity 126 in the longitudinal direction towardconnector 150. The conductive post 130 may be formed integral with theconductor extension 120 or may be formed separately and be press fit,soldered or welded, for example, into a longitudinal hole that is formedin the rear of the internal cavity 126. A distal end 132 of conductivepost 130 may extend longitudinally beyond the internal cavity 126.

The electrical connector 150 may be very similar to the electricalconductor 110. For example, as shown in FIGS. 2A-2C, the electricalconnector 150 includes an elongated metal conductor extension 160 thathas a first end 162 and a second end 164. The conductor extension 160has generally circular cross-sections along the longitudinal direction.A conductor 104-2 of the second electrical cable 102-2 is physically andelectrically connected to the first end 162 of the conductor extension160. The first end 162 of the conductor extension 160 is solid while thesecond end 164 has an internal cavity 166 that has an open end. Thesecond end 164 of the conductor extension 160 also has a lip that formsan annular plate 168 that increases the surface area of the frontsurface of the second end 164 of the conductor extension 160. Theannular plate 168 forms the second electrode of the capacitor 106. Theopen end of internal cavity 126 of connector 110 mates with the open endof internal cavity 166 of connector 150 when connectors 110 and 150 arejoined to form the connector junction 100.

The conductor extension 160 further includes a female contact structurein the form of a spring contact 170 that is positioned within theinternal cavity 166 and that is mechanically and electrically connectedto the conductor extension 160. FIG. 2D illustrates one exampleembodiment of a suitable spring contact 170. The conductive springcontact 170 is configured to receive the distal end 132 of theconductive post 130 of the first electrical connector 110 when the firstand second electrical connectors 110, 150 are mated together. As shownin FIG. 2D, the spring contact 170 may comprise a clasp contact thatincludes a termination post 172, a body 174 that extends from thetermination post 172, and a pair of spring arms 176-1, 176-2 that extendfrom the end of the body 174 that is opposite the termination post 172.The termination post 172 may be, for example, press fit, soldered orwelded into a longitudinal hole that is formed in the rear surface ofthe internal cavity 166. The spring arms 176 may be configured toreceive the distal end 132 of conductive post 130 therebetween when thefirst and second connectors 110, 150 are mated together. The springcontact 170 may be formed of a resilient metal and the spring arms 176may be separated from each other by a distance that is less than thediameter of the conductive post 130 so that the spring arms 176 willexert a contact force on the conductive post 130 when the conductivepost 130 is inserted therebetween.

The connector junction 100 of FIGS. 2A-2C may operate as follows. Aradio frequency signal that is incident on cable 102-1 will pass to theconductor extension 120 of the first connector 110 as the conductor104-1 of cable 102-1 directly contacts the first end 122 of conductorextension 120. As shown in FIG. 2B, the annular plate 128 of conductorextension 120 faces the matching annular plate 168 of conductorextension 160 of connector 150 with the dielectric spacer 134 providedtherebetween. These components together form a capacitor 106 (i.e., twoconductive plates with a dielectric therebetween). Accordingly, aportion of the RF signal energy that passes to conductor extension 120will capacitively couple through the capacitor 106 to the conductorextension 160 of electrical connector 150, and from there will pass tothe conductor 104-2 of cable 102-2 as the conductor 104 directlycontacts the conductor extension 160. Thus, an RF signal that is on thefirst cable 102-1 will capacitively couple to the second cable 102-2through the mated connector junction 100 via a capacitively coupledcommunications path through the capacitor 106.

As discussed above, a direct galvanic communications path may also beprovided between electrical connector 110 and electrical connector 150as the conductive post 130 is directly connected to (or part of)conductor extension 120, the spring contact 170 is directly connected to(or part of) the conductor extension 160, and the conductive post 130 isreceived within and directly contacts the spring arms 176 of springcontact 170 when electrical connector 110 is mated with electricalconnector 150. This galvanically coupled communications path iselectrically disposed in parallel to the above-discussed capacitivelycoupled communications path.

The connector junction 100 may be designed so that the galvanicallycoupled communications path is configured to pass signals in a firstfrequency range and the capacitively coupled communications path isconfigured to pass signals in a second frequency range that is higherthan the first frequency range. In the embodiment of FIGS. 2A-2C, aphenomena known as the skin depth effect may be used (at least in part)to route signals based on their frequency over the appropriatecommunications path. As is known to those of skill in the art, the skindepth effect arises because the changing magnetic field that resultsfrom the alternating current of an RF signal gives rise to opposing eddycurrents in the conductors that carry the RF signal. These eddy currentscause the effective resistance of the conductor to increase at higherfrequencies as a function of the distance from the outer surface of theconductor. As a result, at higher frequencies, most of the current willflow near the surface of the conductor and only a very small amount ofthe current will flow in the middle portion of the conductor.

Referring again to FIGS. 2A-2C, it can be seen that by providing theinternal cavity 126 it is possible to mount the conductive post 130 to acentral portion of the conductor extension 120. Likewise, the springcontact 170 is mounted within the internal cavity 166 so that it issimilarly mounted to a central portion of the conductor extension 160.As such, the direct galvanic connection that is provided in connectorjunction 100 (which passes through the conductive post 130 and thespring contact 170) extends from a central portion of the conductorextension 120 to a central portion of the conductor extension 160. Ifthe RF signals are at reasonably high frequencies, the vast majority ofthe current associated with these signals travels at or near the outerskin of conductor extensions 120, 160, and hence very little current mayflow through the conductive post 130 to the spring contact 170.Consequently, the RF signals may primarily capacitively couple throughthe connector junction 100 and hence PIM may be reduced.

In addition to the above-described RF signal, one or more DC powersupply signals or low frequency control signals may also be transmittedfrom the first cable 102-1 to the second cable 102-2 through theconnector junction 100. As these signals are low frequency signals (andthe power signal may also be a direct current signal), there may belittle or no skin depth effect with respect to these signals, and hencethese signals may travel through the above-described direct galvanicconnection between electrical connector 110 and electrical connector 150(i.e., from the post 132 to the spring contact 172). In light of the lowresistance direct galvanic connection, very little energy from these lowfrequency signals will capacitively couple across the mated connectorsvia the capacitor 106. Thus, the connector junction 100 may capacitivelycouple an RF signal from the first cable 102-1 to the second cable 102-2with little or no PIM while also allowing low frequency power signalsand/or control signals to pass from cable 102-1 to cable 102-2. Thus,the connector junction 100 may be used to pass multiple types ofsignals, and hence may reduce the number of cables and connectors thatare required in various applications.

As noted above, the skin depth effect may limit the amount of current ofa high frequency RF signal that may flow through the direct galvanicconnection between electrical connectors 110 and 150. However, in someapplications, it may be necessary to further limit or prevent the RFsignal from partially flowing through this direct galvanic connection inorder to ensure that PIM is maintained at acceptably low levels. FIG. 3is an exploded, cross-sectional view of a modified connector junction100′ in which substantially all of the RF signal current flow fromconnector 110 to connector 150 will pass through the capacitor 106.

Referring to FIG. 3, it can be seen that the connector junction 100′ isalmost identical to the connector junction 100 of FIGS. 2A-2C. However,in the embodiment of FIG. 3, a connector 110′ is used in place ofconnector 110. In connector 110′, the conductive post 130 of connector110 is substantially shortened and a low pass filter 136 is connected tothe distal end 132 of conductive post 130. A second conductive post 138is attached to the distal end of the low pass filter 136 (i.e., the endopposite the post 132) to extend into the internal cavity 166 of themating connector 150 (part of the low pass filter 136 also extends intothe internal cavity 166 of the mating connector 150 in the depictedembodiment). The post 138 may be received within the spring arms 176 ofspring contact 170 when connector 110′ is mated with connector 150. Thelow pass filter 136 may comprise, for example, an inductor or some otherconfiguration of circuit elements (e.g., capacitors, inductors and/orresistors) that are configured to form a low pass filter thatsubstantially blocks signals above a first frequency from passing fromconductive post 130 to conductive post 138 while allowing signals belowa second frequency to pass from conductive post 130 to conductive post138. The first frequency may be selected to be below the frequency bandof the RF signal, and the second frequency may be selected to be abovethe frequency band of the control signals and/or power signals. Thus, byproviding a low pass filter 136 along the direct galvanic connectionbetween connectors 110′ and 150, the connector junction 100′ of FIG. 3may provide improved PIM suppression. Moreover, the skin depth effectmay also substantially keep the low pass filter 136 out of the RF signalpath so that the low pass filter 136 does not cause substantialintermodulation distortion or other negative effects on the RF signalpath.

While FIGS. 2 and 3 illustrate embodiments in which the connectorjunction 100, 100′ involves a single signal path, more typically anelectrical cable will include two conductors and electrical connectorsthat connect two such cables provide electrical connections for each ofthese conductors. FIG. 4 is a schematic cross-sectional view of aconnector junction 200 in which two coaxial connectors 210, 250 are usedto electrically connect a first coaxial cable 202-1 to a second coaxialcable 202-2.

As shown in FIG. 4, the coaxial cables 202 each include a centerconductor 204, a dielectric layer 206 that circumferentially overliesthe center conductor 204, and an outer conductor 208 thatcircumferentially overlies the dielectric layer 206. Each coaxial cable202 will also typically include an outer protective jacket (not shown tosimplify the drawing) and may include various tapes or otherconventional features known to those of skill in the art.

As is further shown in FIG. 4, a first coaxial connector 210 is mountedon the end of coaxial cable 202-1 and a second coaxial connector 250 ismounted on the end of coaxial cable 202-2. As with the embodimentsdepicted in FIGS. 2 and 3 above, in FIG. 4 the housings of the first andsecond coaxial connectors 210, 250 are not shown to simplify thedrawings and to more clearly illustrate the design and construction ofthe signal paths through the coaxial connectors 210, 250. It will beappreciated that any appropriate housing structures may be used and thatthe housings may include mating attachment structures (e.g., a threadedcoupling nut on one housing and a threaded surface on the other housing)that may be used to draw the coaxial connectors 210, 250 into firmelectro-mechanical engagement. FIG. 4 is an exploded perspective view ofthe connectors 210, 250 in their mated condition. Note that in FIG. 4solder preforms or other structures/materials that may be used toelectrically connect the center conductor 204 of each coaxial cable 202to the center conductor extensions 220, 260 of their associated coaxialconnectors 210, 250 and/or to electrically connect the outer conductors208 of coaxial cables 202 to the outer conductor extensions 240, 280 oftheir associated coaxial connectors 210, 250 are not shown to simplifythe drawings.

The coaxial connector 210 includes a center conductor extension 220, anouter conductor extension 240, and a dielectric spacer 212 thatphysically separates and electrically isolates the center conductorextension 220 from the outer conductor extension 240. The centerconductor extension 220 has the design of the conductor extension 120 ofFIG. 3. In particular, the center conductor extension 220 has a firstend 222 and a second end 224. The first end 222 includes a boss 223extending rearwardly therefrom that is used to physically mount thecenter conductor extension 220 on the center conductor 204 of the firstcoaxial cable 202-1 and to provide an electrical connectiontherebetween. The second end 224 of the center conductor extension 220includes an internal cavity (not visible) that has an open end (seeFIGS. 2B-2C and 3). This internal cavity may be identical to theinternal cavity 126 of coaxial connector 110 that is described above.The second end 224 of the center conductor extension 220 also includes alip that forms an annular plate 228. An annular dielectric disk 234 isattached to the annular plate 228.

The coaxial connector 210 further includes a first low pass filter thatis connected to the conductor extension 220 via a first conductive post.The first low pass filter includes a second conductive post extendinglongitudinally from the distal end thereof beyond the internal cavity226. The low pass filter, first conductive post and second conductivepost may be identical to the low pass filter 136, the first conductivepost 130 and the second conductive post 138 of coaxial connectors 110,110′ that are described above, and hence they are not picturedseparately herein.

The outer conductor extension 240 may have a design that is similar tothe inner conductor extension 220, except that the outer conductorextension 240 is designed to circumferentially surround the innerconductor extension 220 and hence has a larger cross-sectional diameter.In particular, the outer conductor extension 240 has a first end thatincludes a tail 241 that is soldered to the outer conductor 208 of thefirst coaxial cable 202-1 to physically and electrically connect theouter conductor 208 to the outer conductor extension 240. The second endof the outer conductor extension 240 includes an internal cavity 242that has an open end. The second end of the outer conductor extension240 also includes a lip that forms an annular plate 244. An annulardielectric disk 246 may be attached to the annular plate 244.

The center conductor extension 220 is disposed within the internalcavity 242 of the outer conductor extension 240. Additionally, a secondlow pass filter 248 (illustrated schematically in FIG. 4) is providedthat is electrically connected between the outer conductor extension 240and the outer conductor extension 280 of mating coaxial connector 250,which will be described in further detail below. In the depictedembodiment, the second low pass filter 248 is embedded in the annulardielectric disk 246. The second low pass filter 248 may be positionednear outer edges of the annular plate 244 so as to be outside the RFpath (RF energy will flow on the inner surfaces of the outer conductorextensions 240, 280). The second low pass filter 248 may have springcontacts (not shown) on either end thereof to ensure that it makes goodelectrical contact with the outer conductor extensions 240, 280. Whilethe second low pass filter 248 is positioned in the annular dielectricdisk 246 in the depicted embodiment, it will be appreciated that it canbe positioned in a variety of other locations in other embodiments. Forexample, in another example embodiment, a flexible printed circuit board(not shown) that includes the second low pass filter 248 thereon may berolled into a tube and disposed to circumferentially surround the matedcenter conductor extensions 220, 260 in place of the galvanicallycoupled outer conductor communications path that is depicted in FIG. 4.It will be appreciated that numerous other designs are possible.

The coaxial connector 250 may be very similar to the coaxial connector210. The coaxial connector 250 includes a center conductor extension260, an outer conductor extension 280, and a dielectric spacer 252 thatphysically separates and electrically isolates the center conductorextension 260 from the outer conductor extension 280. The centerconductor extension 260 has a first end 262 and a second end 264. Thefirst end 262 includes a boss 263 that is used to physically mount thecenter conductor extension 260 on the center conductor 204 of the secondcoaxial cable 202-2 and to provide an electrical connectiontherebetween. The second end 264 of the center conductor extension 260includes an internal cavity (not visible) that has an open end. Thisinternal cavity may be identical to the internal cavity 126 of coaxialconnector 110 that is described above. The second end 264 of the centerconductor extension 260 includes an outer lip that forms an annularplate 268.

The center conductor extension 260 further includes a spring contact(not shown) that is positioned within the internal cavity thereof thatis mechanically and electrically connected to the center conductorextension 260. The spring contact may be identical to the spring contact170 that is described above with reference to FIG. 2D. The springcontact is configured to receive the second conductive post of the firstlow pass filter of coaxial connector 210 when the first coaxialconnector 210 is mated with the second coaxial connector 250. The springcontact may be press fit, soldered or welded into a longitudinal hole inthe base of the internal cavity 266.

The outer conductor extension 280 has a first end that includes a tail281 that is soldered to the outer conductor 208 of the second coaxialcable 202-2 to physically and electrically connect the outer conductor208 to the outer conductor extension 280. The second end of the outerconductor extension 280 includes an internal cavity 282 that has an openend. The second end of the outer conductor extension 280 also includes alip that forms an annular plate 284. The center conductor extension 260is disposed within the internal cavity 282 of the outer conductorextension 280.

When coaxial connectors 210 and 250 are mated together, the annularplates 228 and 268 are joined together in facing arrangement with thedielectric spacer 234 therebetween to form a first capacitor 209-1.Likewise, the annular plates 244 and 284 are joined together in facingarrangement with the dielectric spacer 246 therebetween to form a secondcapacitor 209-2.

The connector junction 200 will thus have a center conductorcommunications path that electrically connects the center conductor 204of the first coaxial cable 202-1 to the center conductor 204 of thesecond coaxial cable 202-2. The connector junction 200 will also have anouter conductor communications path that electrically connects the outerconductor 208 of the first coaxial cable 202-1 to the outer conductor208 of the second coaxial cable 202-2. The center conductor extensioncommunications path will include a capacitively coupled center conductorcommunications path that passes through the capacitor 209-1 and agalvanically coupled center conductor communications path that passesthrough the first low pass filter. The outer conductor extensioncommunications path will include a capacitively coupled outer conductorcommunications path that passes through the capacitor 209-2 and agalvanically coupled outer conductor communications path that passesthrough the second low pass filter 248.

The connector junction 200 of FIG. 4 will operate like a conventionalcapacitively coupled connector junction for RF signals that are presenton either cable 202-1 or 202-2, as the skin depth effect and/or thefirst and second low pass filters will substantially prevent the RFsignals from passing through the galvanically coupled center or outerconductor communications paths. Low frequency control signals and/or DCpower signals may pass through the mated connector junction 200 via thegalvanically coupled center or outer conductor communications paths, butwill generally not pass through the capacitively coupled center or outerconductor communications paths as the capacitors 209-1, 209-2 will actas high pass filters that will substantially prevent the low frequencycontrol signals and/or DC power signals from traveling along thecapacitively coupled communications paths.

While the coaxial connector junctions according to embodiments of thepresent invention may be used in many different applications, they maybe particularly well-suited for use in cellular base stations. FIG. 5schematically illustrates a cellular base station 300 in which thecoaxial connector junction 200 of FIG. 4 may be used. As shown in FIG.5, the cellular base station 300 includes an equipment enclosure 310 anda tower 320. Three baseband units 312 and a power supply 316 are locatedwithin the equipment enclosure 310. Three remote radio heads 330 andthree antennas 332 are located at the top of the tower 320.

As shown in FIG. 5A, the base band unit, or BBU 312, is attached to theremote radio head 330 by a combination of a fiber optic cable and apower cable (or by a hybrid cable which is a single cable with fiberoptic and power elements combined into a single unit). This arrangementprovides power for the remote radio heads 330 and/or the antennas 332,as well as the signal to be radiated from the antenna and controlsignals. The remote radio heads 330 are connected to the antennas 332 bycoaxial cables 344 that are terminated with coaxial connectors. Thesecoaxial connectors may be connected to mating coaxial connectors on theremote radio heads 330 and antennas 332 to form coaxial connectorjunctions 370. For example, coaxial connector junctions 370 may beprovided at each connection between remote radio heads 330 and eachcoaxial cable 344 (junctions 370-3) and between each coaxial cable 344and an antenna 332 (junctions 370). Each coaxial cable junction 370 maybe implemented, for example, using the coaxial connector junction 200 ofFIG. 4.

Referring again to FIG. 5, the antennas 332 may, for example, include anactuator that moves or electrically adjusts internal elements forpurposes of beam steering or may be a gimbaled antenna that is driven bya motor. In either case, control signals may be used to control theantenna 332. Typically, these control signals are generated at the baseof the tower 320 (or elsewhere) and must be transmitted up the tower 320to the antennas 332 to control the antennas 332 Additionally, the remoteradio heads 330 and the beam shaping circuit and/or motor on theantennas 332 will require power signals to operate (typically a DC powersignal). In conventional cellular base stations, a separate cable istypically routed from the enclosure 310 to the top of the tower 320 andthe control signals and power signal are transmitted up the tower 320over this separate cable. Additional connectors are also typicallyrequired at both the top of the tower and the bottom of the tower toconnect the power/control signal cable to the equipment at eachlocation. The inclusion of the separate cable and connectors may resultin a number of disadvantages, including increased equipment costs,increased wind and weight loading on the tower and increasedinstallation costs.

However, when coaxial connector junctions according to embodiments ofthe present invention are used the RF signals from the baseband units312, the DC power signals from the power supply 316 and the controlsignals from a controller (not shown) may all be transmitted up thetower 320 on the coaxial cables 342, 344, thereby eliminating the needfor one or more additional cables.

FIG. 6 is a circuit diagram of a coaxial connector junction 400according to embodiments of the present invention. As shown in FIG. 6, atransmission line 410 is provided. In the example of FIG. 6, thetransmission line 410 is a 50 ohm transmission line. A first signalsource 420 is provided that may be used to inject a low frequency signalonto the transmission line 410. A second signal source 430 is providedthat may be used to inject a high frequency RF signal onto thetransmission line 410. A load 440 is provided at the end of thetransmission line 410.

As shown in FIG. 6, both the first and second signal sources 420, 430are capacitively coupled to the load 440 through a two-sidedcapacitively coupled communications path 450 that includes first andsecond capacitors 452. The first and second signal sources 420, 430 aregalvanically coupled to the load 440 through a two-sided communicationspath 460 that includes a pair of low pass filters 462.

The connector junctions according to embodiments of the presentinvention such as connector junctions 100, 200, 300, 400 may exhibit anumber of advantages. First, as noted above, the connector junctions100, 200, 300, 400 may be used to pass both high frequency RF signalsalong with one or more low frequency control and/or power signals. Thismay reduce the number of cables and connectors that are required invarious applications such as the number of cables that must be run up anantenna tower at a cellular base station.

Additionally, one potential problem with conventional capacitivelycoupled coaxial connector junctions is that the outer conductors of thetwo connectors that form the junction may not be at the same electricalpotential since the outer conductors of the two connectors are notdirectly electrically connected to each other. If moisture accumulateson the exposed outer surface of the outer conductors of the twoconnectors it may provide an electrical path between the two outerconductors. If a potential difference exists between the two conductors,it will encourage a flow of electrical ions from the outer conductorextension at the higher potential to the outer conductor extension atthe lower potential, which results in galvanic corrosion to the outerconductor extensions. However, since the electrical path through thesecond low pass filter appears as a direct galvanic connection to lowfrequency signals, the outer conductor extensions will be maintained atthe same potential and the above-described mechanism for corrosion ofthe outer conductor extensions may be reduced or eliminated.

FIG. 7 is a flow chart diagram that illustrates a method of reducingcorrosion in a connector junction according to certain embodiments ofthe present invention. As shown in FIG. 7, a first capacitively coupledcommunications path may be provided between a conductor of a firstconnector and a conductor of a second connector (block 500). A secondgalvanically coupled communications path may also be provided betweenthe conductor of the first connector and the conductor of the secondconnector (block 510). The second galvanically coupled communicationspath is electrically parallel to the first capacitively coupledcommunications path and is configured to maintain the conductor of thefirst connector and the conductor of the second connector at the sameelectrical potential (block 520).

Moreover, the connector junctions according to embodiments of thepresent invention may also provide a low frequency ground path that maybe used to dissipate lightning strikes that transfer energy to, forexample, a coaxial cable that is routed up an antenna tower. When alightning strike transfers energy to a coaxial cable, this energy tendsto be carried by the outer conductor of the coaxial cable. Theelectrical energy imparted to the outer conductor may have a very highvoltage. Accordingly, if this electrical energy passes to equipment thatis attached to the coaxial cable it has the potential to damage ordestroy such equipment. Typically, small portions of the jacket of acoaxial cable that is routed up an antenna tower will be removed andconductive ground straps are connected between the outer conductor andthe tower. As the tower is formed of metal and as the base of the toweris grounded, the conductive straps provide low resistance ground pathsthat may be used to pass the electrical energy of a lightning strike toground.

Typically, the electrical energy of a lightning strike appears as a lowfrequency signal. When capacitively-coupled connector junctions are used(to reduce PIM), the capacitive connection between the outer conductorextensions of two mated connectors tends to block the energy of thelightning strike. As such, it may be necessary to ground each and everycable segment between the enclosure and the equipment at the top of thetower. This may be difficult and/or inconvenient to do with respect tocable segments at the top of the antenna tower. However, when theconnector junctions according to embodiments of the present inventionare used, the second galvanically coupled outer conductor communicationspath may be used as a conductive path for carrying energy of thelightning strike to a ground strap to dissipate the energy of alightning strike.

The connectors according to certain embodiments of the present inventionmay include a both a first capacitively coupled signal path that be usedto pass high frequency signals to a mating connector as well as a secondgalvanically coupled communications path. The connectors are designed sothat they can be connected and disconnected from other mating connectorswhile still providing these parallel paths.

It will be appreciated that numerous modifications may be made to theexample embodiments that are discussed above without departing from thescope of the present invention. For example, in the embodimentsdiscussed above, the annular dielectric disks that form the dielectricof the various capacitors are mounted on the conductor extensions of theconnector that includes the low pass filters. In other embodiments, anyother appropriate arrangement may be used, such as mounting these diskson the connectors that include the spring contact structures or on bothof the connectors of a connector junction. It will also be appreciatedthat the low pass filters may be included in either or both connectorsof a connector junctions. As another example, the plate capacitorarrangement illustrated in the connectors of FIGS. 2-4 may be replacedwith other capacitor designs. Moreover, the galvanic connection betweenthe two outer conductor extensions of a mated connector junction may beoutside the outer conductor extensions. Such a design may require abetter low pass filter, as it may not use the skin depth effect toprovide isolation between the capacitive and galvanic signal paths. Insome embodiments, some or all of the internal cavities provided on theconnectors may be omitted.

While the present invention has been described above primarily withreference to the accompanying drawings, it will be appreciated that theinvention is not limited to the illustrated embodiments; rather, theseembodiments are intended to fully and completely disclose the inventionto those skilled in this art. In the drawings, like numbers refer tolike elements throughout. Thicknesses and dimensions of some componentsmay be exaggerated for clarity.

Spatially relative terms, such as “under”, “below”, “lower”, “over”,“upper”, “top”, “bottom” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. It will beunderstood that the spatially relative terms are intended to encompassdifferent orientations of the device in use or operation in addition tothe orientation depicted in the figures. For example, if the device inthe figures is turned over, elements described as “under” or “beneath”other elements or features would then be oriented “over” the otherelements or features. Thus, the exemplary term “under” can encompassboth an orientation of over and under. The device may be otherwiseoriented (rotated 90 degrees or at other orientations) and the spatiallyrelative descriptors used herein interpreted accordingly.

Well-known functions or constructions may not be described in detail forbrevity and/or clarity. As used herein the expression “and/or” includesany and all combinations of one or more of the associated listed items.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”,“comprising”, “includes” and/or “including” when used in thisspecification, specify the presence of stated features, operations,elements, and/or components, but do not preclude the presence oraddition of one or more other features, operations, elements,components, and/or groups thereof.

Herein, the terms “attached”, “connected”, “interconnected”,“contacting”, “mounted” and the like can mean either direct or indirectattachment or contact between elements, unless stated otherwise.

The foregoing is illustrative of the present invention and is not to beconstrued as limiting thereof. Although exemplary embodiments of thisinvention have been described, those skilled in the art will readilyappreciate that many modifications are possible in the exemplaryembodiments without materially departing from the novel teachings andadvantages of this invention. Accordingly, all such modifications areintended to be included within the scope of this invention as defined inthe claims. The invention is defined by the following claims, withequivalents of the claims to be included therein.

1. A coaxial connector junction, comprising: a first coaxial connectorthat includes a first center conductor extension and a first outerconductor extension; and a second coaxial connector that is mated withthe first coaxial connector, the second coaxial connector including asecond center conductor extension and a second outer conductorextension; and wherein a communications path between the first outerconductor extension and the second outer conductor extension includes afirst capacitively coupled outer conductor communications path and asecond galvanically coupled outer conductor communications path.
 2. Thecoaxial connector junction of claim 1, wherein the first capacitivelycoupled outer conductor communications path is configured tosubstantially pass signals having frequencies in a first frequency rangewhile substantially blocking signals having frequencies in a secondfrequency range that encompasses frequencies that are lower than thefirst frequency range, and wherein the second galvanically coupled outerconductor communications path is configured to substantially passsignals having frequencies in the second frequency range whilesubstantially blocking signals in the first frequency range.
 3. Thecoaxial connector junction of claim 1, wherein a communications pathbetween the first center conductor extension and the second centerconductor extension includes a first capacitively coupled centerconductor communications path and a second galvanically coupled centerconductor communications path.
 4. The coaxial connector junction ofclaim 3, wherein the first capacitively coupled center conductorcommunications path is configured to substantially pass signals havingfrequencies in a first frequency range while substantially blockingsignals having frequencies in a second frequency range that encompassesfrequencies that are lower than the first frequency range, and whereinthe second galvanically coupled center conductor communications path isconfigured to substantially pass signals having frequencies in thesecond frequency range while substantially blocking signals in the firstfrequency range.
 5. The coaxial connector junction of claim 3, whereinthe first center conductor extension includes an outer shell thatdefines an internal cavity, and wherein the first capacitively coupledcenter conductor communications path extends along the outer shell andthe second galvanically coupled center conductor communications pathextends through the internal cavity.
 6. The coaxial connector junctionof claim 5, wherein the second galvanically coupled center conductorcommunications path includes an inductance that is at least partlywithin the internal cavity.
 7. The coaxial connector junction of claim1, wherein the first outer conductor extension includes an outer shellthat defines an internal cavity, and wherein the first capacitivelycoupled outer conductor communications path extends along the outershell and the second galvanically coupled outer conductor communicationspath extends through the internal cavity.
 8. The coaxial connectorjunction of claim 7, wherein the second galvanically coupled outerconductor communications path includes an inductance.
 9. The coaxialconnector junction of claim 1, wherein the first outer conductorextension is spaced apart from and circumferentially surrounding thefirst center conductor extension and the second outer conductorextension is spaced apart from and circumferentially surrounding thesecond center conductor extension.
 10. The coaxial connector junction ofclaim 1, wherein the first capacitively coupled outer conductorcommunications path and the second galvanically coupled outer conductorcommunications path comprise parallel paths that are configured to carrysignals in different frequency ranges. 11-22. (canceled)
 23. A coaxialconnector comprising: a center conductor extension that has an outershell that defines an internal cavity and a center conductor contactthat is electrically connected to the center conductor extension anddisposed within the internal cavity; an outer conductor extension thatis spaced apart from and circumferentially surrounding the centerconductor extension; and a dielectric spacer interposed between thecenter conductor extension and the outer conductor extension thatelectrically isolates the center conductor extension from the outerconductor extension.
 24. The coaxial connector of claim 23, wherein thecenter conductor contact is configured to mate with a center conductorcontact of a mating coaxial connector.
 25. The coaxial connector ofclaim 23, wherein the center conductor contact includes a low passfilter.
 26. The coaxial connector of claim 23, further comprising acoupling nut that is configured to releasably attach the coaxialconnector to a mating coaxial connector so that the center conductorextension capacitively couples with a center conductor extension of themating coaxial connector and the outer conductor extension capacitivelycouples with an outer conductor extension of the mating coaxialconnector, and so that the center conductor contact galvanically mateswith a mating center conductor contact of the mating coaxial connector.27. The coaxial connector of claim 26, wherein the center conductorextension of the mating coaxial connector comprises an outer shell thatdefines an internal cavity, and wherein the mating center conductorcontact of the mating coaxial connector is electrically connected to thecenter conductor extension of the mating coaxial connector.
 28. Anelectrical connector, comprising: an outer conductor extension having acable receiving end and a connection end opposite the cable receivingend; a center conductor extension having a first end that is configuredto physically and electrically engage a conductor of a communicationscable that is received within the cable receiving end of the outerconductor extension and a second end that comprises an outer shell thatdefines an internal cavity; and a center conductor contact that iswithin the internal cavity.
 29. The electrical connector of claim 28,wherein the outer shell is configured to capacitively couple with acenter conductor extension of a mating electrical connector, and whereinthe center conductor contact is configured to physically engage a centerconductor contact of the mating coaxial connector to provide parallelcommunications paths between the electrical connector and the matingelectrical connector.
 30. The electrical connector of claim 29, whereinthe center conductor contact includes a low pass filter.
 31. Theelectrical connector of claim 28, wherein the outer shell includes anexpanded capacitive coupling surface.